While vitamin K is certainly an essential nutrient, and your aim should be to receive a sufficient amount of this vitamin every day, there’s something you should know about vitamin K. As a key player in the process of forming blood clots to help stop bleeding from wounds, vitamin K can counteract the effects of medications that thin the blood. Blood-thinning medications (also known as anticoagulants), like coumadin or warfarin, reduce the formation of blood clots in adults who are at risk for heart attacks, stroke or arterial blockage. Since vitamin K can increase the activity of blood clotting, it is important that adults taking such prescriptions pay special attention to their vitamin K intake. Check both your multivitamin and the foods you regularly eat for their vitamin K content. Vitamin K is found in all cruciferous vegetables, such as broccoli, Brussels sprouts, cabbage, and cauliflower, so use caution if you regularly eat these foods and also take blood-thinning medication. It is OK to eat vitamin K-containing food, just so long as you don’t overdo it.